traffic-split: update root service selector & targetPort usage

[shashankram]

Description:
This change does the following:

1. Fixes the incorrect legacy behavior where traffic
   directed to a root service specified in a TrafficSplit
   resource can direct traffic to pods that do not match
   the root service's selector. Not only was this behavior
   confusing, it also significantly complicated code paths
   that required special handling of this scenario that is
   unintuitive. Going forward, the root service selector
   must match pods for traffic splitting to those pods to
   function. Existing e2e tests relying on this unsupported
   behavior have been updated to correctly configure selectors
   and labels on services and pods backing them. A redundant
   test explicitly testing the only supported scenario after
   this change has been removed. The automated demo has
   also been updated to correctly configure the selector and
   labels.

2. Fixes Specifying root service port to a port other than containerPort/TargetPort of the leaf service doesn't not work #4894, where the TargetPort on the root service was
   expected to match the ContainerPort on the pod backing
   the service. Per SMI's TrafficSplit API, the TargetPort
   on the root does not need to match the ContainerPort
   on the pod, thus allowing newer application versions
   to change the ports they listen on without needing
   to update the root service definition.

Testing done:
Unit tests, e2e tests

Affected area:

Functional Area
SMI Policy	[X]

Please answer the following questions with yes/no.

1. Does this change contain code from or inspired by another project? no

   • Did you notify the maintainers and provide attribution?

2. Is this a breaking change? yes

3. Has documentation corresponding to this change been updated in the osm-docs repo (if applicable)? traffic-split: update root service usage osm-docs#413

[codecov-commenter]

Codecov Report

Merging #4902 (0dd11db) into main (d5d3a25) will decrease coverage by 0.08%.
The diff coverage is 71.69%.

@@            Coverage Diff             @@
##             main    #4902      +/-   ##
==========================================
- Coverage   68.73%   68.64%   -0.09%     
==========================================
  Files         220      220              
  Lines       15934    15938       +4     
==========================================
- Hits        10952    10941      -11     
- Misses       4930     4945      +15     
  Partials       52       52              

Flag	Coverage Δ
unittests	68.64% <71.69%> (-0.09%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pkg/k8s/mock_controller_generated.go	12.96% <0.00%> (-1.18%)	⬇️
pkg/k8s/types.go	100.00% <ø> (ø)
pkg/catalog/outbound_traffic_policies.go	92.74% <83.33%> (-2.92%)	⬇️
pkg/k8s/client.go	94.98% <87.50%> (-0.84%)	⬇️

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[keithmattix]

LGTM, love to see code removed